It is unlawful to remove a person from an office or position of public trust because such person has not complied with any law, charter, or regulation prescribing an additional test or qualification for such office or position of public trust, other than tests and qualifications provided for under civil service and retirement laws, whenever such person:

(a)Holds the office or position of public trust, and

(b)Upon entering upon the office or position of public trust, has taken, or after his election or appointment, has offered to take the oath of office prescribed by this article.